Method of and apparatus for automatically grinding cathode ray tube faceplates

ABSTRACT

A workpiece manipulating apparatus for faceplate panels of cathode ray tubes includes a conveyor for carrying panels along two groups of grinder stations in a pattern coordinated with carriage mounted loaders which move along the conveyor. The conveyor indexes to loading stations as do the loaders. Unground panels are sequenced to the stations as the loaders are present. Loaders pick the unground panels from the conveyor and transfer them to an orienting station which orients panels for loading into a grinder. Loaders pick an oriented panel from the orienting station and load it in to the grinder at the loading station. They also pick up ground panels from the grinder and place them in a reorient station and pick ground panels from the reorient station and place them on the conveyor in the position from which they removed an unground panel. The loader advances to a next loading station to load a next grinder and the conveyor with panels picked up at the preceeding station. The cycle is continuous with the panel manipulation through a complete cycle approximating the grinding time of a panel in a grinder.

This invention relates to methods of and apparatus for automaticallygrinding cathode ray tube (CRT) faceplates, and more particularly, tomethods and apparatus for assigning and delivering CRT faceplates todesignated ones of a plurality of grinding machines, identifying themachine in which a CRT faceplate is ground, loading the CRT faceplateinto the machines, and removing CRT faceplates from the machines.

Heretofore, it has been known to grind the outer surface of thefaceplates of CRTs to improve the optical quality of the images formedupon the faceplates. Such grinding operations have been performed ingrinding machines of various forms including machines, hereinafterdesignated "singlehead grinders", having a single elastomeric wheel,rotating around a generally horizontal axis, and to which a slurry ofabrasive is fed while a carriage is traversed in a generally horizontalplane to carry a rotating CRT faceplate chuck beneath the wheel so thatthe wheel rides over the contour of a suitably chucked faceplate. Inproduction, an aligned array of singlehead grinders are positionedadjacent a conveyor for CRT faceplates which furnishes raw or ungroundfaceplates to the area and carries ground faceplates from the area. Anattendant transferred faceplates from the conveyor to the singleheadgrinder, seated them properly in the nest blocks of the grinder chucks,started the grinder after it was properly loaded, and returned to removethe ground faceplate and placed it on the conveyor at the end of thegrinder cycle. Since the grinding cycle consumed more time than thefaceplate transfers, the attendant was usually assigned to service aplurality of grinders.

Significant time was lost in the manual loading and unloading of thegrinders. Ware was occasionally passed through the grinding stationwithout being transferred to the grinders. As CRT faceplates have becomelarger, the ware is quite heavy and it has become difficult to load intoand remove from the grinders. Production rates are dependant upon theskill, strength and endurance of the machine attendants.

An object of the present invention is to improve the manufacture of CRTfaceplates, to increase the uniformity of processing, to increase thespeed of loading and unloading grinders and to reduce the cost ofmanufacture of high quality CRT faceplates. Further, objects are toreduce the labor of attending the grinding of faceplates, to enhance theaccuracy of loading a faceplate into a grinder and to identify theground faceplates with the grinding machines upon which they wereground.

In accordance with the above objects, a feature of this invention is aCRT faceplate handling method and system adapted to receive faceplates,load them on a conveyor, mark them with an identification code for thegrinding machine to which they are assigned, orient them on the conveyorfor transfer to the assigned grinding machine, advance them along a pathadjacent a plurality of grinding machines and transfer them between theconveyor and the assigned grinding machine. Transfer of CRT faceplatesis accomplished by a transfer mechanism which picks up a faceplate onthe conveyor and a ground faceplate in a grinder machine simultaneouslytransfers the faceplates to carrier stations, advances along theconveyor to a position adjacent another grinder machine, transfers theunground faceplate on its carrier station into the adjacent grindermachine while removing a ground faceplate from that machine andtransfers the unloaded ground faceplate to a carrier station which hasbeen vacated by a previously ground faceplate which is transfered to theconveyor at a location from which an unground faceplate had been removedto the transfer mechanism carrier station for unground faceplates.

The transfer mechanism is on a carriage, the motion of which isprogrammed to pick up an unground faceplate which has been preassignedto the next following grinder machine in the carriage motion program.The conveyor is programmed to present an assigned CRT faceplate to thestation immediately preceeding the grinder machine into which thefaceplate is to be loaded and to handle faceplates for the entiresystem.

The number of grinders serviced by a system and the speed of theconveyors and transfer mechanisms is advantageously matched to the timeinterval of a grinder machine so that a carriage with its transfermechanism is positioned adjacent the machine and poised to unload andreload the machine with raw ware as it concludes its grinding cycle. Ina disclosed arrangement two carriage mounted transfer mechanisms arepositioned on opposite sides of a conveyor having a row of grindermachines on each side. The transfer mechanisms travel between theconveyor and the grinding machines. One transfer mechanism loads half ofthe machines on the side which it services before the cycle of the othertransfer mechanism is initiated and when the system is in full operationthe transfer mechanisms operate out of phase by one half theirrespective service cycles.

Drive motors are provided for the conveyor to index CRT faceplates tothe centerlines of grinder machines aligned with each other across thelongitudinal dimension for the conveyor. Electric motors also drive thecarriages of the transfer mechanisms to center those mechanisms on thegrinder machine centerlines. The transfer functions of the transfermechanism are driven by electric motors and pneumatic cylinders.Conveyor loading and CRT faceplate marking and positioning are alsodriven by pneumatic cylinders. All of these mechanisms have controls theoperation of which is coordinated by a master control which may be aprogrammable controller.

The above and additional objects and features of this invention will beappreciated more fully from the following detailed description, whenread with reference to the accompanying drawings, in which:

FIG. 1 is a schematic plan view one arrangement of theconveyor-marker-loader-grinder apparatus of this invention;

FIG. 2 is a fragmentary sectional view of the apparatus of FIG. 1 takenalong the line 2--2 of FIG. 1 showing loaders which have positioned CRTfaceplates above the conveyor and the grinder machines, the loadershaving their orient and reorient stations cooperating homestation armsand panel lifting and holding mechanisms removed for illustrativepurposes;

FIG. 3 is a schematic sectioned plan view taken at 3--3 of FIG. 2,showing on an enlarged scale one loader positioned along the conveyor ata loading station with the loader head removed to illustrate thestations of the loading machine;

FIG. 4 is an enlarged partially sectioned elevational view of a loaderwith its conveyor and grinder unloading arms taken along the line 4--4of FIG. 3 and its carriage, track and drive including a phantom view ofthe grinder unloading position in a grinder with the reorientingstation, the conveyer loading arm and the mechanisms which it carrieseliminated for illustrative purposes;

FIG. 5 is an enlarged partially sectional elevational fragmentary viewof the loader of FIG. 4 taken from a position shifted 90° from FIG. 4 orfrom the position viewed along the lines 5--5 of FIG. 3 to illustratethe conveyor loading and grinder loading arms positioned above theircarrier dwell positions in which a CRT faceplate panel can be orientedfor loading into a grinder and reoriented for return to conveyor;

FIG. 6 is a plan view of the grinder chuck aligning mechanism arrangedto insure rotational postioning of the grinder chuck to receive a CRTfaceplate panel;

FIG. 7 is a timing chart for a conveyor and loader cycle; FIGS. 8Athrough 8E is a timing chart the sheets of which when placed inhorizontal alignment along their length dimension shows the progress ofpanels through the apparatus from conveyor loading through distributionto loading stations to pickup by the loaders, loading into the grinderto which they were assigned and, after a grinding interval, unloadingfrom the grinder and return to the conveyor;

FIG. 9 is a block diagram of a typical motor the control system of whichcontrols and coordinates the acceleration, velocity, position and timingof the motor driven conveyors and loader carriages to perform thefunctions represented in FIGS. 7 and 8A through 8E; and

FIG. 10 is an overall block diagram of the sensing and control means forthe system to illustrate their relationships to the programmablecontroller.

A schematic layout of the apparatus of this invention is shown in FIG. 1as applied to sixteen grinder machines 21 arranged in two rows of eightmachines, one on each side of a conveyor 22 for CRT faceplate panels tobe ground in the system. A loading cradle 23 is located at the input endof conveyor 22 and is arranged as a paddle pivoted at its lead end 24below the conveyor surface so that its down stream portion extends atabout a sixty degree inclination to the conveyor ware support surface.

Conveyor 22 comprises several sections, a feed section 32, a mainsection 33, and a delivery or output section 30. Feed conveyor 32coordinates the introduction of CRT faceplates to be ground in thesystem with the operation of the remainder of the system's elements. Aloading section 25 of conveyor 32 is made up of slave driven rollers.The rollers 26 adjacent the loading cradle 23 extend from each side ofthe conveyor bed edge to a cavity 27 between those rollers into whichthe loading cradle 23 is depressed as it is pivoted to deposit a panelon the loading section 25. The rollers 28 down stream of rollers 26extend the full width of the conveyor bed from the cradle through amarker-positioner station 29 to a belt conveyor section 31.

Marker-positioner station 29 includes apparatus to pick up a CRTfaceplate on the fly as it is advanced on rollers 28 and raise thefaceplate to a position at which a coded identification of the grinderto which the faceplate is assigned is applied to the skirt of thefaceplate. Such coded markings can be applied through elastomeric maskspressed against the faceplate skirt as by sand blasting (by means notshown). The station 29 also includes chucks which are closed upon thefaceplate while it is lifted free of the conveyor to orient it forreplacement on the conveyor in a position for handling in subsequentmanipulations (by means not shown).

Feed conveyor 32 is driven in the roller and belt portions as a slave tomain conveyor 33, which is of the belt type, by means of a chain driveand a clutch coupling it to the main conveyor so that the feed conveyor32 and main conveyor 33 function as a single continuous conveyor whencoupled. Alternatively the feed conveyor 32 is declutched from the mainconveyor and driven by its own motor and control.

Conveyors 32 and 33, when coupled, function as a single continuousconveyor which is indexed to advance CRT faceplate panels returned tothe feed conveyor 32 at marker-positioner station 29 to the severalgrinder machine stations. In the illustrated arrangement, the firstgrinder machines of the groups on each side of the feed conveyor 32 arepositioned with the centerlines normal to the longitudinal dimension orconveying direction of the conveyor and coincident. This coincidentcenterline arrangement is maintained for opposed grinder machines of theremainder of each machine group which are adjacent the main conveyor 33.The grinder machine stations on the conveyor are such that the CRTfaceplates on the conveyor are stopped centered on the grinder machinecenterlines. Grinder machine centerlines are spaced equally along theconveyor and the spacing from the marker-positioner station 29 to thefirst grinder machine station is equal to the spacing of adjacentcenterlines. The conveyor sections index in increments of the spacing ofadjacent centerlines or multiples thereof.

In order to facilitate further discussion of the system and itsfunctions, the grinder machines 21 will be designated as machines 1through 8 on the righthand side of the conveyor 22 as viewed in theconveying direction and as machines 9 through 16 on the lefthand side.With such designations, the coincident machine centerlines extendingacross the conveyor will represent the stations to which CRT faceplatespanels are advanced by the conveyor or carried by the loaders. The eightstations are identified by their machine numbers based upon thecenterlines as stations 1-9, 2-10, 3-11, 4-12, 5-13, 6-14, 7-15, 8-16.In discussing the manipulation of individual panels, the stations forthe panels on the indexing conveyor are referenced from themarker-positioner station in station-to-station increments such as a oneincrement indexing of feed conveyor to station 1 or a two incrementindexing to station 2 from the marker-positioned when the panel isassigned to one of the righthand group of grinders 1 through 8. When thepanel is to be processed by a machine on the left, those on the set 9through 16, the first station to which they are advanced will bedesignated as station 9 for a single increment index and station 10 fora double increment index. It should be appreciated that station 9 iscoincident with station 1 on the conveyor and station 10 is coincidentwith station 2. Since the loaders are individual to the group ofmachines they service, their locations will be designated by the machinecenterline on which they are centered as loader stations 1 through 8 forthe righthand loader stations and 9 through 16 for the lefthand loader.

A first grinder machine 21 of each group of machines, machine 1 andmachine 9, is located along the side of the feed conveyor 32. Theremaining seven grinder machines 21 of each group, machine 2 through 8and 10 through 16, are located along the sides of the main conveyor 33.Transfer of CRT faceplates or panels from the conveyor deck or belt 40to the grinders is by means of loaders 34 and 35 for the righthand andlefthand group of machines 21 respectively (as viewed along thedirection of conveyor advance) each having a carriage 36 and 37 which isadapted for movement along the conveyor between the conveyor 22 and themachines 21 on rails 38, 39 and 41, 42 as best seen in FIG. 2. Thecarriages are driven by individual motors 43 and 44 which drive a pinion45 and 46 engaging a rack 47 and 48 mounted on and extending along theconveyor base frame 49 from stations 1-9 to 8-16. Suitable controlscause the drive motors to advance the carriages along the conveyor toposition the loader axis on the centerline of the grinder machine 1through 8 or 9 through 16 with which it is programmed to function.

The loaders 34 and 35 each have four arms 51, 52, 53 and 54 which are inquadrature and which are normal to a generally vertical axis in thecarriage and are rotatable about the axis through an arc of 90° from ahome position to a deliver position. In the illustative example, eachloader advances its arms clockwise from the home positions, a forwardindex, and returns its arms from the delivery postions to the homepositions with counter-clockwise motion, a reverse index. The arms areabove the level of the conveyor deck and the grinder machine faceplatesupporting surfaces which are essentially at the same level.

Conveyor unloading arm 51 has a home postion extending toward theconveyor normal to the conveying direction and carries a four barlinkage mechanism 55 driven by a pneumatic cylinder 56 to move a vacuumcup 57 faceplate pickup head over and down upon a faceplate on theconveyor.

The four bar linkage comprises two bell cranks 58 and 59 pivoted on arm51 at 61 and 62 coupled by a link 63 pivoted at 64 and 65. Drivecylinder 56 is pivoted at its blind end on the loader at trunion 66 andhas its piston rod 67 pivoted to crank 59 at 68. Vacuum head mountbracket 69 is integral with link 63 and is maintained with an axis ofthe vacuum head and cup 57 vertical throughout its translation betweenits retracted and extended positions by the four bar linkage 55 so thata CRT faceplate 71 maintains its seal edge 72 in a generally horizontalplane as it is engaged and lifted from the conveyor deck 70. Thedelivery position of arm 51 is above an orienting station 73.

Grinder loading arm 52, as shown in FIG. 5, has a home position along aline parallel to the longitudinal axis of the system, the conveyor andcarriage advance direction, and above an orienting station 73 on thecarriage. It has a four bar linkage mechanism 74 driven by a pneumaticcylinder 75 to move a vacuum cup 76 in the same manner and for the sameCRT faceplate manipulating functions as is the case for arm 51. Theorienting station 73 comprises a support shelf 77 extending from thecarriage 34 along the longitudinal axial direction of the system betweenthe conveyor and the aligned grinder machines. The support shelf 77 hasan overlying support plate 78 which is vertically moveable relative tothe shelf by means of pneumatically driven elevator cylinder 79 securedto the shelf. Cylinder 79 has a shaft 81 which will lower and raise thesupport plate according to a program to be discussed. Elastomeric pads80 on the support plate engage the seal edge of a faceplate panel 71 tosupport it during a dwell and orient function. When the support plate 78is lowered by cylinder 79, it carries portions of the CRT faceplate sealedge 72 into orienting blocks 82 which straddle the pads 80, as shown inFIG. 3, and the support plate 78 and pick up the seal edge to guide thefaceplate by a camming action into a final oriented position for loadinginto the grinder machine 21. The delivery position of arm 52 is parallelto the grinder machine centerline.

Grinder unloading arm 53, shown in FIGS. 2 and 4, carries a grindermachine unloading head which carries a vacuum cup 83. Its home positionis along a line perpendicular to the longitudinal axis of the system andthus, when the carriage has brought the loader to a machine loadingstation, its axis is in the plane normal to the conveyor deck andcontaining the grinder machine centerline. Arm 53 is above the shroud 84of the grinder machine 21 and clear of the hood 85. It has a four barlinkage mechanism 86 driven by a pneumatic cylinder 87 to move thevacuum cup 83 between a retracted and raised position in which it cansupport a CRT faceplate free of the grinder and an extended anddepressed position in which it engages a ground faceplate on the grinderchuck 88. A vacuum head mounted bracket 89 is integral with the four barlinkage 86 and maintains the axis of the head and cup vertical while itis extended and retracted so that CRT faceplate engaged by the vacuumcup 83 is maintained with its seal edge in a generally horizontal plane.The delivery position of arm 53 is above a support table 92 between thealigned grinder machines and the conveyor, as best seen in FIG. 5.

A typical down and extended position of a vacuum cup is shown in phantomin FIG. 4 for grinder unloading arm 53. Each of arms 51, 52 and 54 havesimilar four bar linkages, pick up heads and vacuum cups which are movedto the down and extended position by selectively actuating pneumaticcylinders through solenoid controlled valves individual to the arms.Cylinders also drive the linkages and pick up heads to their up orretracted condition by solenoid valve controlled pneumtic driving force.

The conveyor loading arm 54, shown in FIG. 5, has mechanisms similar toarms 51, 52 and 53 for maniplating a vacuum cup 91 to pick up a CRTfaceplate from a support table 92 on the carriage 36 and position it tobe placed on conveyor 32 or 33. It has a four bar linkage 93 having anintegral vacuum head mount bracket 94 which maintains the axis of thehead and cup 91 perpendicular while it is advanced and lowered orretracted and raised by pneumatic cylinder 95. The delivery position ofarm 54 is perpendicular to the longitudinal dimension of conveyor 22.The dwell station 100 to which CRT faceplates are delivered from thegrinder machine 21 by grinder unloading arm 53 and from which faceplatesare transfered to the conveyor by conveyor loading arm 54 is locatedbetween the aligned grinder machines 21 and the conveyor 22. The dwellstation may include a reorienting mechanism to shift the faceplate nintydegrees around a central axis perpendicular to its face therebyidentifying the faceplate as one which has been ground when it is placedon conveyor deck 40 with its major axis perpendicular to the conveyingdirection. Such a reorienting mechanism can be provided with theelements shown in FIG. 5 modified to rotate the support table 92 in 90°increments as a turntable, mounted on a rotatable shaft 97 supported ina journal 98 and driven by a selectively actuable drive 96 on a bracket99 extending from carriage 36. A motor 101 is arranged to drive shaft 97through a quarter turn so that faceplates placed on support table 92 arereoriented in quadrature to the position they were received from thegrinder and will be in quadrature relative to unground faceplates whenplaced on the conveyor deck.

Arms 51, 52, 53 and 54 are driven clockwise, as viewed from above,through an arc of ninty degrees from their home stations by rotationalmotion of a vertical shaft 102 journalled on carriage 36. A Ferguson camindex 103 provides oscillating motion for shaft 102 to drive the shaftclockwise and simultaniously to carry the arms 51, 52, 53 and 54 totheir delivery positions and then drive it counterclockwise to returnthe arms 51, 52, 53, 54 to their home positions. The cam 103 is drivenwith a variable speed motor 104 so that motion of the arms can becontrolled as to acceleration and velocity.

Faceplates at the orient station 73 and the reorient or dwell station100 are raised to engage the raised vacuum cups 76 and 91 by applyingpneumatic pressure to their elevating cylinders 79 and 110 to moveshafts 81 and 97 axially of their cylinders and upward. After asufficient pause in the raised position to enable vacuum to be appliedto cups 76 and 91, the support plate 78 and its support blocks arelowered to clear the seal edge 72 of the vacuum held faceplate panel inorient station 73 and the support table 92 is lowered to clear the sealedge 72 of the vacuum held panel in reorient or dwell station 100.

The vacuum cups 57, 76, 83 and 91 are caused to seize and support theCRT faceplate panels with which they are engaged by a vacuum imposedwithin their skirts. They also are arranged to release panels positivelyby application of positive air pressure within their skirts. A closedvalve within each cup has an opening plunger extending into the skirtedarea so that the valve is open when the skirt is seated on a surface,such as a faceplate panel. A conduit (not shown) extends from a controlvalve (not shown) in communication with a source of vacuum and a sourceof positive air pressure. Selective control as by a solenoid control ofthe control valve applies either vacuum or positive pressure to thevacuum cup plunger valve. If the cup is engaged with a panel so that theplunger valve is open, vacuum or positive pressure will be appliedwithin the cup depending upon the control signal to the control valve.

With the loader at a station supplied a raw or unground panel by theconveyor and adjacent a grinder which has a ground panel on its mandrel,and with a raw panel in the orient station of the loader and a groundpanel in the dwell or reorient station, the loader will advance panelsat each of its positions. First, air is admitted to cylinders 56 and 87to extend and lower cups 57 and 83 into engagement with a raw panel 71on the conveyor and a ground panel 71 in the grinder. Vacuum is appliedto the cups and the plunger actuated valves therein are open to seizeand support the panels against the cups. The orient and reorientelevators are elevated by pneumatically actuating cylinders 79 and 110to raise the panels at those stations into engagement with vacuum cups76 and 91. Vacuum is applied to cups 76 and 91 to seize and support thepanels. While vacuum is maintained on cups 57 and 83, the cylinders 56and 87 are actuated so the linkages and panels are retracted and raised.With vacuum maintained on cups 76 and 91, the orient and reorientelevators are lowered through operation of cylinders 79 and 110. Theloader shaft is rotated clockwise one quarter turn to index all arms 51,52, 53 and 54 and their supported panels forward to the next loaderquadrant. The raw panel from the orient station on arm 52 is extendedand lowered to place the panel seal edge on the nest blocks on thegrinder chuck and the ground panel from the reorient station on arm 55is extended and lowered to place the seal edge on the conveyor byadmitting air to cylinder 75 and 95. The orient and reorient elevatorsare raised to bring pads 80 into supporting engagement with the sealedge of the raw panel picked from the conveyor by cup 57 and the table92 into engagement with the seal edge of the ground panel picked fromthe grinder by cup 83. Vacuum is released and positive pressure air isapplied to each of the cups to free them from their respective panels.Linkages 74 and 93 with their cups 76 and 91 are raised and retacted.All cups are free and clear of ware and the loader arms are returned totheir home position by counterclockwise rotation as a reverse indexoepration. Thus, each of the linkages on the arms extend and lower theircups when their arms are normal to the conveying direction and eachmaintain their arms retracted and raised when their arms are parallel tothe conveying direction. In the orient and reorient stations, paneltransfer is by motion of the seal edge support with respect to the sealedge of the panel through raising and lowering those supports bycylinders 79 and 110. Cylinders 55, 74, 86 and 93 driving theirrespective four bar linkages raise and lower the vacuum cups to transferpanels at the conveyor and grinder. Following a panel transfer at astation, the unloaded cups, their support brackets, manipulatinglinkages and drive piston rods are retracted to provide clearancepermitting the loader to be positioned at the next grinder in itssequence for another loading and unloading cycle.

Each grinder 21 comprises a tray 105 mounted for horizontalreciprocation normal to the conveying direction (by means not shown) andsupporting a horizontal chuck 88 mounted for rotation in the tray abouta vertical axis on shaft 106. A drive motor and gear box 107 are carriedby the tray carriage for rotation of the chuck 88 during grinding asperformed by a rubber tired wheel (not shown) rotated above the carriageand within a hood 85. A slurry of abrasive is the grinding medium and itis contained by the hood 85 and shroud 84 mounted around the traycarriage. Chuck 88 has a flat surface on which elastomeric nest blocks111 are positioned to engage the faceplate adjacent its corners andretain it for rotation with the chuck as the tray 105 and thus the chuckis fed into the grinding tire at a speed programmed in accordance withthe degree of material removal desired at various portions of thefaceplate engaged by the tire. Upon completion of grinding, the tire israised, the tray is extended toward the conveyor 22 and the chuck isaligned with the major axis of the rectangular CRT faceplate parallel tothe longitudinal axis of the conveyor. This locates the ground faceplateso that when picked up by the vacuum cup on grinder unloading arm 53 itwill be properly oriented for the dwell or reorient station 100 and thefollowing return to the conveyor. Also the chuck 88 and its nest blocks111 are oriented to receive the unground faceplate from the orientingstation 73.

The drive for grinder chuck 88 is controlled to stop rotation with thechuck in its load-unload position, with the faceplate major axisparallel to the conveying direction. An interlock, FIG. 6, assures thatthis position has been achieved as by means of a switch 112 whichenables the loader 34 or 35. If switch 112 is not actuated when thegrinder motor 107 is stopped, the loader 34 or 35 is inhibited and ahoming cam driver is actuated to drive the chuck 88 to its load-unloadposition. A cam 113 is keyed to chuck shaft 106 with flats 114 locatedto cooperate with a drive link 115 having a mating flat 116. Drive link115 is pivoted on the tray carriage at 117 and is driven by a pneumaticcylinder 118 having its blind end pivoted on the carriage at 119 and itspiston rod 121 coupled to link 115 at clevis 122. Thus, if switch 112 isnot activated due to a misalignment of chuck 88, loader 34 or 35 isinhibited and cylinder 118 is supplied air to extend rod 121 drivinglink 115 toward shaft 106 and into engagement with cam 113. Flat 116 isdriven against cam flat 114 causing cam 113 and shaft 106 to rotate intothe load-unload position. This actuates switch 112 which causes thecylinder 118 to retract rod 121 and cam driver link 115 from cam 113while also enabling unloader 34 or 35 so that the operation can proceed.

Conveyor 33 is driven by a motor and drive 123 mounted on conveyorsupport frame 49 and having controllable speed and distance of advanceas by means of an a.c. motor driven by a variable frequency inverterthrough a reduction gear (not shown). Chain 124 couples conveyor 33 toconveyor 32 through clutch 125. When clutch 125 decouples the conveyors,conveyor 32 can be driven independently of conveyor 33 by a motor anddrive 108 mounted upon conveyor support frame 49. Motor and drive 108can also be controlled as to the speed and distance of advance ofconveyor 32 by means of an a.c. motor driven by a variable frequencyinverter through a reduction gear (not shown).

The operation of the system will be recited with respect to the flow ofa single CRT faceplate 71 with reference to FIG. 7. A faceplate 71 ismanually loaded on cradle 23 with its major axis, if it is rectangular,generally parallel to the conveying direction and its seal edge 72 down.The loaded cradle pivots into cavity 27 between feed conveyor rollers 26so that the faceplate seal edge 72 is supported upon those rollers. Thedrive for rollers 26 advance faceplate 71 to rollers 28 and into themarker-positioner station 29 where it is picked up on the fly and markedwith its assigned grinder code, reoriented for further handling by theclosure of jaws on the faceplate skirt 127 and returned to the conveyorrollers 28. It is then advanced on belt conveyor 31 one or two machinespacing increments to the centerline between the first or second pair ofgrinder machines, depending upon the sequence of its introduction, to bediscussed.

Faceplate 71 is picked up by its loader 34 or 35 one machine positionahead of the grinder machine in which it is to be ground and aftergrinding it is reloaded on the conveyor one machine position followingthe grinder machine in which it was ground. When it reaches a positionadjacent a loader, it is picked up and advanced to the orient station onthe loader. The loader is then advanced one machine station. Thefaceplate is picked up from the loader orient station and loaded intothe grinder placing its seal edge 72 on chuck 88 with its skirts 127 innest blocks 111. The loader advances to the next machine and the grindercontaining the faceplate proceeds with its grinder cycle.

When properly adjusted with respect to conveyor and loader timing, thesystem will return the loader to the machine grinding faceplate 71 asthe grinding operation is concluded with the chuck properly aligned inthe load-unload position and the grinder tray fully extended toward theconveyor. The loader cycle is performed and the unloading arm extendsits vacuum head into the grinder machine to pickup faceplate 71, retractthe vacuum head and faceplate, and index it to the dwell or reorientstation. The loader then advances to the next machine station andrepeats its cycle so that the conveyor loading arm 54 picks up thefaceplate from the dwell station on the loader and places it on theconveyor 22. It should be noted that the regular feeding of faceplatesto the conveyor in the defined sequence assures that a vacant faceplateposition is available to which the ground faceplate can be returned.That is, a raw faceplate is removed from the conveyor and a groundfaceplate is placed in the position from which the raw faceplate wasremoved.

The main conveyor 33 then continues indexing in two machine stationincrements until it delivers the faceplate 71 to a continuously runningtakeout conveyor 30 which may be of the belt type driven by motor 128and carries the faceplate to the next processing position.

The above sequence is performed in an integrated operation including thetwo loaders to that during normal operation the conveyor receives rawfaceplates at regular intervals, faceplates which are unground and thosewhich are ground are positioned on the conveyor. Each loader manipulatesfour faceplates simultaneously and transports two faceplates on itsorient and dwell stations to the next machine. The loaders 34 and 35 aremaintained with a separation of one half a grinder machine group, i.e.in the eight machine groupings having machines 1 through 8 in therighthand group served by loader 34 and machines 9 through 16 in thelefthand group served by machine 35. Loader 34 starts at station 1, itshome station, while loader 35 stands by at station 9, its home station.Loader 34 picks up at station 1, advances to station 2 and deposits itsfaceplate in machine 2 while picking up a faceplate delivered byconveyors 32 and 33 at station 2. It then advances to 3 depositing thefaceplate picked up at station 2 and picking up a raw faceplate fromconveyor 33. Again it advances to station 4 depositing the faceplatepicked up at station 3 and picking up a new faceplate. It then advancesto station 5, the fifth of the eight stations and four stations fromloader 35 at station 9. Both loaders 34 and 35 operate with thisseparation along the conveyor. Loader 34 picks up at a raw faceplate atstation 5 and loads the faceplate picked up at station 4 into machine 5and loader 35 picks up a raw faceplate at station 9. Both loaders areadvanced one station and the main conveyor advances two stations. Loader34 picks up at station 6 and loads the station 5 pick up into machine 6while loader 35 picks up at station 10 and loads the station 9 pick upinto machine 10. This pattern of operation continues so that when loader34 has picked up and loaded at station 8, loader 35 has picked up andloaded at station 12. Loader 34 then returns to its home station 1 whereit picks up a faceplate from feed conveyor 32 and deposits the faceplatepicked up at station 8 in the grinder machine at station 1.

At the next advance of loader 34 the faceplate picked up at station 1 isloaded into grinder 2 while the faceplate ground in grinder 2 during theloader scan of machines 3 through 2 is transfered to the dwell stationof loader 34. Loader 34 advances to station 3 to load the ungroundfaceplate picked up at 2 onto grinder 3 and to load the ground faceplatepicked up from machine 2 onto conveyor 33.

When loader 34 is advanced from station 4 to 5, loader 35 is returnedfrom station 16 to its home station 9. With the loading by loader 35 ofthe faceplate picked up at station 16 into machine 9 the system is fullyloaded, all machines are functioning to grind faceplates and the loadercycles each involve the manipulation of four panels resulting in theremoval of an unground faceplate from the conveyor and the placement ofa ground faceplate on the conveyor in its stead.

The apparatus is controlled by a programmable controller 131 asillustrated in block diagram form in FIGS. 9 and 10. The controllerreceives electrical signals as system inputs which indicate the state orposition of the equipment and control changes in the state or position.

In one arrangement, ware is placed on the loading cradle 23 and aphotosensor 132 detects the presence of the ware for the controllerwhich enables loading when feed conveyor 32 signals, as from its motorcontrol 133, that the conveyor is stopped. The load cradle pivots downto deposit the ware and the input conveyor 32 is started to advance theware along rollers 26 to rollers 28. A ware sensor 134 detects thearrival of ware at the marker-positioner station and causes the warelift in that station to pick up the ware for marking with the code ofthe grinder to which the ware is assigned for grinding. The marker isenabled only if the grinder is operating and has transmitted anoperating signal to controller 131. Controller otherwise assigns theware to the next available grinder in the system according to itsassignment routine and causes the marker to apply the code for thatgrinder and the ware to be returned to the conveyor by the marker at thetime appropriate for conveyance to the assigned grinder.

The ware marker-positioner 29 is the mechanism for establishing thespacing, location along the length, and orientation of the ware on theconveyors 32 and 33 as controlled by the controller 131 in causing themarker-positioner lift to return the ware to the conveyor rollers 28.Set down of ware is enabled only when the conveyor 31 is stopped andissues an enable signal through the controller. Once the lift hasdeposited the ware on the conveyor, indicated by station transducer 135signal, and conveyor 31 has moved it out of the marker-positionerstation as indicated by the ware clearance sensor 136, themarker-positioner station is enabled to pickup the next piece of ware.

The controller program establishes the interaction of the grinders andloaders. Grinders 21 issue signals as by switch 112 when they are readyto receive ware and when the loader has been positioned at the stationfor the ready grinder the controller causes the loader to load ware intothe grinder. If a loader is moved in the program of its movements to agrinder which is out of service, the controller 131 will inhibit loadingand the loader will not go through its loading motions. If the grinderis not ready for loading when the loader is present at its station, aswhere the grinder chuck 88 is not oriented to its load-unload positioneither because the grinder cycle has not been completed or the chuck wasnot stopped at the load-unload position, the loader will stand at thestation and an indication of a non-operating condition issued.Orientation of the chuck 88 will enable the loader in the sequencedescribed with reference to FIGS. 4 and 6.

Operation of the loaders is also controlled by controller 131. A localloop responsive to an enable and inhibit signal from controller 131controls the loader carriage drives as will be described. Once a loadercarriage is positioned at a loading station, the control of thepneumatic actuators for the motion of the heads on the loader arms, thecontrol of the lifts at the orient and reorient stations and the controlof vacuum or blow off air to the vacuum cups is by means of signals fromthe controller 131 to solenoid valves in the lines supplying pneumaticpressure, vacuum and blow off air.

The grinders 21 are controlled by individual controllers and are subjectto controller 131 enable and inhibit signals as are the conveyors 30, 32and 33. Conveyor 30 runs continuously when enabled. Conveyors 32 and 33have local control loops for position acceleration and velocity of theirdrives.

At the discharge of the system, ware sensors 137 and 138 are provided toinsure that ware does not stack up. Sensor 137 is at the input end ofthe takeout conveyor and 138 is at the discharge end. If ware is sensedat both sensors, the conveyors are stopped by controller 131.

FIG. 7 illustrates a timing cycle of the major functions of the systemunder fully loaded conditions, the cycle being measured from thecompletion of the cradle 23 loading of a faceplate 71 on rollers 26through the second following completion of such loading. Immediatelypreceeding the cycle, ware on cradle 23 is lowered onto the conveyor asa "down" function of Manual Load Cradle. The main conveyor 33, which iscoupled to the feed conveyor 32, advances two increments, that is twocenterline to centerline spacings, thus causing the feed conveyor toadvance two increments between time 0 and 7.5 at Feed Conveyor. Thiscarries the loaded ware into the ware marker station 29 where it ispicked up on the fly while a previously advanced piece of ware atposition 1-9 is advanced two stations to position 3-11 and all otherware distributed along main conveyor 33 is advanced two stations. In theware marker 29, the newly picked up piece of ware is lifted then chuckedto proper alignment for placement in the conveyor, marked and as thefeed conveyor stops set down on the feed conveyor.

Assume loader 34 and its carriage 36 were at station 2, centered onposition 2-10 of FIG. 1, and had a raw panel on its orientor which itpicked up from the conveyor at station 2, and a finished panel on itsdwell or reorientor which it picked up from grinder 2. Also assume thatthe loader arms 51, 52, 53 and 54 of loader 34 are in their forwardindex position with arm 51 in the orienting station 73, its arm 52perpendicular to the conveying direction, its arm 53 in the dwell orreorient station 100 and its arm 54 over the conveyor 33. All vacuumcupheads are retracted. The carriage 3 is traversed in the interval 0 to7.5 at Traverse Carriage function to advance the carriage one spaceincrement from station 2 to station 3. During this traverse the arms arereverse indexed 90° to position arm 51 over conveyor 33, arm 52 inorient station 73, arm 53 perpendicular to the conveyor and arm 54 inthe dwell reorient station 100 as signified in Index 90° function as areverse index. With carriage 36 stopped, the loader is enabled if thegrinder 3 chuck 88 is in its load-unload position and conveyor is notmoving.

As indicated at the Pickup/Unload function of FIG. 7 between the 8 and12 time increment limits the vacuum heads on arms 51 and 53 are actuatedby pneumatic drive of cylinders 56 and 87 to engage vacuum cup 57 withthe raw panel 72 advanced to station 3 and to engage vacuum cup 90 withthe ground panel chuck 88 in grinder 3. The orient lift cylinder 79, 79and reorient lift cylinder 95 receive pneumatic drive to raise supportplate 78 and its raw panel from the orienting blocks 82 into engagementwith vacuum cup 76 and to raise table 92 and its ground panel fromgrinder 2 into engagement with vacuum cup 91. Vacuum is applied to allcups and the engaged panels are seized by their vacuum cups during the"down-pause" portion of the Pickup-Unload function with the "up-pause"portion of the Orient and Reorient functions occuring in time interval 8to 10.5. In the balance of the interval for those functions from timeinterval 10.5 to 12 the vacuum heads on arms 51 and 53 are raised tolift the panels from the conveyor 33 and grinder 3 and the orient andreorient lifts are depressed to free the panels supported by the vacuumheads of arms 52 and 54.

With all arms supporting suspended panels, the loader 34 is rotated 90°clockwise indicated at function Index 90° by "forward index" interval attime 12 to 14. The arms then release their panels at the advancestations. The raw panel for orientor blocks 82 is deposited on grinder 3chuck nest blocks 111 and the ground panel from dwell or reorientstation 100 is deposited on conveyor 33 by extending and lowering vacuumheads on arms 52 and 54 through pneumatic drive control of cylinders 75and 93 as indicated at function Load Grinder/Conveyor at time intervals14 to 16.5 designated "down pause". During this interval, the raw panelin the orient station is engaged by plate pads 80 and the ground panelfrom machine 3 is engaged by support table 92 through pneumatic drivesto cylinders 79 and 110 as at functions Orient and Reorient "up pause"intervals. The vacuum is relieved in vacuum cups 57, 76, 90, 91 and blowoff air is imposed in those cups to release the panels during this "uppause" interval. The vacuum heads on arms 52 and 54 are raised andretracted through pneumatic drive control of cylinders 75 and 93 asindicated at function Load Grinder/Conveyor interval "up" between times16.5 and 18. The panels are lowered from vacuum cups 57 and 90 on arms51 an 53 by pneumatic drives to cylinders 79 and 110 at functions Orientand Reorient in intervals "down" of time periods from 16.5 to 18. Theloader head is free of all panels at this moment and is clear of theconveyor and grinder 3 so that its carriage can advance in the nextcycle which is a repetition of that outlined above and depicted in FIG.7.

In operating as a system shown in FIG. 1 the cycles of operation are asshown in FIGS. 8A through 8E. In those cycles, as illustrated, eachpanel is identified by distinctive cross hatching of the intervals ofoperating functions effective upon that panel. Those functions, whichoperate upon no panel are shown as lines in the manner illustrated inFIG. 7. Notations of the conveyor transport of panels are included asare advanced of the carriage 36 of loader 34 and 37 of loader 35, theloading of the grinders by number, and the transfer of finished panelsto the conveyor are presented as notes on the drawings.

As shown in FIGS. 8A through 8E, the panels are assigned for grinders inthe order as depicted from left to right at function Manual Load Cradle:2, 3, 4, 5, 6, 7, 8, 1, 10, 11, 12, 13, 14, 15, 16, 9 and repetitivelythereafter (shown as primed numbers) so long as all grinders areoperative. The grinders and panel are all of the same type, hence,grinder cycle intervals for a given panel type should be indentical inlength. The system is arranged so that the panel loading cycle for allgrinders is completed as or before the grinder cycle so that the loadersystem should be the limiting factor in an ideal arrangement. In anyevent, a grinder must complete its cycle even if the loader system isrequired to wait to unload the grinder.

A typical operation on the first panel, the panel assigned grinder 2 isillustrated by the solid time function bars. Thus. panel 2 is loaded bythe cradle preceeding the first cycle it is fed to marker by feedconveyor driven by main conveyor, marked and after the feed conveyor isstopped, placed on feed conveyor all in the first portion of the cycle.In a second portion of the first cycle, it is fed to station 1 by thefeed conveyor as indicated by the legent "TO 1", it is picked up byloader 34 at station 1 which is forward indexed to the orienter.Following the feed conveyor advance driven by the main conveyor, thesecond panel is loaded as panel 3 designated as a bar which is neithercrosshatched nor shaded. Panel 3 is fed to the ware marker in the firstcycle of the system and returned by the marker to the feed conveyor.

In the second system cycle a normal cycle as described for FIG. 7 isperformed since the loader has advanced to station 2 and need not beconcerned with the motion of the feed conveyor and its possibledisruption of the Pick Up/Unload function. Panel 2 is transported tostation 2 on the orienter of loader 34 and in the second half of thesecond cycle is unloaded into grinder 2 as a transfer from the orientstation 73 to the grinder through a pickup function, a 90° advance indexand a load function. Panel 3 is advanced from the marker to station 2 ofthe conveyor by traversing feed conveyor 32 and into main conveyor 33.Panel 3 is picked up and placed in orient station 73. Panel 4 is fed byfeed conveyor to the marker. Panel 5 is loaded on the stopped feedconveyor in the first portion of the second system cycle.

In the terminal portion of the second system cycle panel 3 is picked upindexed and placed in the orient station 73. The feed conveyor advancesone space increment to move panel 4 to station 4. Panel 5 is advanced tothe marker and marked and panel 6 is loaded on the stopped feedconveyor.

The third cycle involves manipulation of panels 3, 4, 5, 6, 7, and 8.Panel 3 is carried by loader 34 to station 3 and loaded in grinder 3.Panel 4 is advanced to station 3 by feed and main conveyors is picked upby loader 34 and is placed in orientor 73. Panel 5 is advanced tostation 2 by feed and main conveyors. Panel 6 is advanced to the marker,marked and advanced to station 1. Panel 7 is loaded on feed conveyor,advanced to marker, and marked. Panel 8 is loaded on the feed conveyor.

In the fourth cycle, as shown in FIG. 8B, the handling of panels forboth groups of grinders is begun with the loading of panel 10. Panels 4,5, 6, 7, 8, 1 and 10 are handled in this cycle. Panel 4 is advanced withloader 34 to station 4, picked up from the orientor and loaded intogrinder 4. Panel 5 is advanced to station 4, is picked up by loader 34and transfered to orientor 73. Panel 6 is advanced to station 3 by mainconveyor. Panel 7 is advanced to station 2 by feed and main conveyor.Panel 8 is advanced to the marker, marked, oriented and placed on feedconveyor and advanced to station 1. Panel 1 is loaded, advanced to themarker, marked. oriented and placed on the feed conveyor. Panel 10 isloaded.

In the fifth cycle, as shown in FIG. 8B, panels 5, 6, 7, 8, 1, 10, 11and 12 are handled and loader 35 comes into operation at station 9 inposition 1-9. Panel 5 is advanced with loader 34 to station 5, picked upfrom the orientor and loaded into grinder 5. Panel 6 is advanced tostation 5, is picked up by loader 34 and transferred to orientor 82.Panel 7 is advanced to station 4 by the main conveyor. Panel 8 isadvanced to station 3 by the feed and main conveyor. Panel 1 is advancedto station 2 by the feed and main conveyor. Panel 10 is advanced to themarker, picked up, oriented, marked and returned to the feed conveyorand advanced to station 1 from which it is picked up by loader 35 afterthe feed conveyor has stopped. Panel 11 is loaded, advanced to themarker, picked up, oriented, marked and set down on the feed conveyor.Panel 12 is loaded.

In the sixth system cycle, as shown in FIG. 8C, panels 6, 7, 8, 1, 10,11, 12, 13 and 14 are handled, carriage 37 makes its initial traversefrom station 9 to station 10 and both loaders 34 and 35 are fullyoperative. Panel 6 is advanced with loader 34 to station 6, picked upfrom the orientor and loaded into grinder 6. Panel 7 is advanced tostation 6, picked up and placed in the orientor of loader 34. Panel 8 isadvanced to station 5. Panel 1 is advanced to station 4. Panel 10 isadvanced with loader 35 to station 10 and picked up from the orientor ofloader 35. Panel 11 is advanced to station 10 by the feed and mainconveyor and is picked up by loader 35. Panel 12 is advanced to themarker, picked up, oriented, marked, returned to the feed conveyor andadvanced to station 9. Panel 13 is loaded, advanced to the marker,picked up, oriented, marked, and returned to the feed conveyor after itstops. Panel 14 is loaded.

In the seventh system cycle, as shown in FIG. 8C, four raw panels areadvanced on the main conveyor. Panels 7, 8, 1, 10, 11, 12, 13, 14, 15and 16 are handled. Panel 7 is advanced with loader 34 to station 7,picked up from the orientor of loader 34 and loaded into grinder 7.Panel 8 is advanced to station 7, picked up and placed in the orientorof loader 34. Panel 1 is advanced to station 6. Panel 10 is loaded intogrinder 10. Panel 11 is placed in the orientor of loader 35, advancedwith loader 35 to station 11, and picked up from the orientor of loader35. Panel 12 is advanced to station 11 and picked up by loader 35. Panel13 is advanced to station 11 by the feed and main conveyor. Panel 14 isadvanced to the marker, picked up, oriented, marked, returned to thestationary feed conveyor, then advanced to station 9 by the feedconveyor. Panel 15 is loaded, advanced to the marker, picked up,oriented, marked and returned to the feed conveyor. Panel 16 is loaded.

In the eighth cycle, as shown in FIG. 8C, functions corresponding tothose of the seventh cycle are performed with panels 7 and 10 droppedout and panels 9 and 2' added. Panel 2' is the first of a second cycleof panels and will be ground in grinder 2. Loader 34 loads grinder 8which is at the end of its traverse and loader 35 advances to station12.

In the ninth cycle, shown in FIG. 8D, loader 34 initiates a returntraverse to its home position at station 1. The time consumed in thatreturn exceeds a normal system cycle and since timing relationships aremaintained with respect to loader position and the transport of panelsby the feed and loader conveyors, some alteration of the routine occurs.Panels 1, 12, 13, 14, 15, 16, 9, 2', 3', 4' are handled. Panel 1 iscarried toward station 1 by the loader as it returns. Panel 12 is loadedinto grinder 12 by loader 35. Panel 13 is advanced to station 13 in theorientor of loader 35 and picked up. Panel 14 is advanced to station 13on conveyor 33 and picked up by loader 35. Panel 15 is advanced tostation 13 on conveyor 33 and 16 is advanced to station 11 on feedconveyor 32 and main conveyor 33. Panel 9 is advanced by feed and mainconveyor to station 10. Panel 2' is advanced to station 1 by the feedconveyor. Panel 3' is loaded, advanced to the marker, picked up,oriented, marked and returned to the conveyor. Panel 4' is loaded.

A delay is introduced in conveyor indexing, as shown in FIG. 8D, for aninterval sufficient to permit loader 34 to complete its return traverseto station 1 and load panel 1 in grinder 1 while picking up panel 2'from the feed conveyor at station 1.

Regular cycling of the system resumes, as shown in FIG. 8D, in the tenthcycle in which panels 13, 14, 15, 16 and 9 of the initial cycle, and 2',3', 4', 5' and 6' of the second system cycle are handled. Panel 13 isloaded into grinder 13 by loader 35. Panel 14 is placed in the orientorof loader 35 advanced to station 14, and picked up in the orientor ofloader 35. Panel 14 is advanced to station 14 on conveyor 33 and ispicked up by the loader 35. Panel 16 is advanced to station 13 onconveyor 33. Panel 9 is advanced to station 13 by conveyor 33. Panel 2'is advanced to station 2 by loader 34 and loaded into grinder 2 afterpanel 2 of the first system cycle has been removed from grinder 2 andplaced in reorient or dwell station 100 of loader 34. At this time, andfor following regular cycles, loader 34 will manipulate a panel at eachof its four vacuum heads. Panel 3' is advanced by conveyors 32 and 33 tostation 2, is picked up by loader 34 and placed in its orientor. Panel4' is advanced to marker 29 by conveyor 32, picked up, oriented, marked,returned to the stationary conveyor 32 and advanced to station 1 byconveyor 32. Panel 5' is loaded, advanced to marker 29 by conveyor 32,picked up, oriented, marked, and returned to the stationary conveyor 32.Panel 6' is loaded.

The eleventh cycle, shown in FIG. 8E, returns the first ground panel tothe conveyor, panel 2, and transports to the next station the first of araw panel, panel 3', and a ground panel, panel 2, on the loader 34. Inthis cycle, panels 14, 15, 16, 9, 2, 3, 3', 4', 5', 6', 7' and 8' arehandled. Panel 14 is loaded into grinder 14 by loader 35. Panel 15 isplaced in the orientor of loader 35, advanced with the loader to station15 and picked up from the orientor. Panel 16 is advanced to station 15on conveyor 33 and is picked up by loader 35. Panel 9 is advanced tostation 14 by conveyor 33. Ground panel 2 is advanced to station 3 inloader 34 reorient dwell station and transferred to the conveyor in thelocation from which panel 4' was removed by loader 34. Ground panel 3 isremoved from grinder 3 and placed in reorient dwell station 100 ofloader 34. Raw panel 3' is removed from orientor and loaded into grinder3. Panel 4' is removed from conveyor 33 and placed in orienting station73 of loader 34. Panel 5' is advanced by conveyor 33 to station 4. Panel6' is advanced by conveyor 32 to marker 29, picked up, oriented, marked,returned to conveyor 32 and advanced to station 1 by conveyor 32. Panel7' is loaded, advanced by conveyor 32 to marker 29 picked up, oriented,marked and returned to conveyor 32. Panel 8' is loaded.

System cycle twelve is similar to cycle eleven, as shown in FIG. 8E.Ground panel 3 is returned to the conveyor at station 4 from which panel5' was removed, grinder 4 has ground panel 4 unloaded and panel 4'loaded and grinder 15 is loaded by loader 35 with panel 15.

System cycle thirteen, as shown in FIG. 8E, returns loader 35 to itshome station, station 9, carrying panel 9. Ground panel 4 is returned toconveyor 33 by loader 34 in the position from which raw panel 6' wasremoved. Loader 34 unloads ground panel 5 from grinder 5 and loads rawpanel 5' into grinder 5.

In the fourteenth cycle (not shown) loader 35 has returned to its homestation and loads panel 9 into grinder 9 while picking up panel 10' fromfeed conveyor 32 at station 9. Thus, a second cycle of the panelsassigned the left bank of grinders 21 begins while the loader 34continues its unloading, orienting, loading, reorienting, and reloadingfunctions at each of grinder 6, 7, 8, 1, 2, 3, 4 and 5.

In the fifteenth cycle (not shown) loader 35 begins to handle threepanels simultaneously. At station 10, it picks up panel 11' fromconveyor 33 and places it on its orient station; advances panel 10' fromits orient station to grinder 10, removes ground panel 10 from grinder10 and places it in the reorientor or dwell station 100. Loader 34continues its handling of four panels at station 6.

In the sixteenth cycle, and thereafter, (not shown) both loaders 34 and35 are handling four panels simultaneously. Loader 35 at station 11returns ground panel 10 to conveyor 33, loads raw panel 11' in machine11, picks raw panel 12' from conveyor 33, and unloads ground panel 11from machine 11.

With all grinders functioning and panels loaded at regular intervals,the system as illustrated loads 16 raw panels per system cycle and offloads 16 ground panels continuously. If a grinder is out of operation,the controller 131 prevents the placement of a panel assigned thatgrinder on feed conveyor 32 and inhibits the coding of that grinder on apanel at marker 29. The loader servicing the non-operating grinderadvances to the grinder station but does not perform any grinder loadingor unloading functions.

In shutting down the system, the feed of raw panels is terminated andthe loaders continue to run until they have unloaded the last panel fromtheir dwell reorient stations. They would then return to their homestations and conveyors would continue to run until all panels had beenoff loaded at output conveyor 30.

The indexing motion of the conveyors 32 and 33 and the loader carriages36 and 37 is controlled with respect to acceleration, velocity andposition or displacement and position and motion is indicated andcommanded by the controller 131. Each of conveyors 32 and 33 have driveswhich have local control loops which can comprise a position feedbackloop and velocity feed back loop as typified in FIG. 9 by the motorcontrol system 140. System 140 has a motor 141 having a tachometer 142and a displacement encoder 143 driven by the motor shaft. The velocityfeedback loop 144 comprises the tachometer 142, a servomotor control 145and the motor 141. The displacement and position feedback loop 146includes encoder 143, which can be a pulse generator for digitallyindicating displacement increments and/or a digitally encoded positionindicator, which feeds a micromotion profiler 147 coupled through theservo motor control 145 to the motor 141. The micromotion profiler 147is coupled through a suitable interface 149 to a programmable controller131 serving the entire system so that command and position, velocityand/or acceleration signals can be exchanged between profiler 147 andcontroller 131 to control the motor and indicate the state of theapparatus which it drives. One suitable profiler is a PMI MicromotionModule from PMI Motors, a division of Kollmorgen Corporation, 5 AerialWay, Syosset, N.Y.

Motor 141 typically drives a reduction gear 148 which in the case offeed conveyor 32 and its drive motor 126 is coupled through anoverriding clutch 139 to a drive chain for rollers 26, 28 and beltconveyor section 31. In the case of main conveyor 33 and its drive motor123, the typical motor 141 and gearing 148 is coupled to a drive for theconveyor belt 70 forming the deck of the main conveyor 33 and is coupledas by overriding clutch 125 and coupling chain 124 to drive conveyor 32as a slave to conveyor 33. Thus when main conveyor 33 is driven by itsmotor and drive 123 feed conveyor 32 is driven and clutch 149 permitsmotor 126 to remain idle. Conversely, when motor 126 drives feedconveyor 32 clutch 125 permits main conveyor 33 and its drive 123 toremain idle. Each motor control of the conveyor drives 123 and 126 havemotor control elements and couplings to the controller 131 as discussedwith respect to the typical motor control 140.

As illustrated, a typical motor control system 140 is arranged to drivea pinion 149 such as drive pinion 45 of loader carriage 36 or drivepinion 46 of loader carriage 37. Thus, such motor control systems areillustrated in FIG. 10 as system 150 for carriage 36, 151 for carriage37, 152 for main conveyor 33 and 133 for feed conveyor 32 all subject tocontrol and coordination of operation as programmed in controller 131.Takeout conveyor motor control is treated as an on-off control 155subject to control of controller 131.

The ware marker-positioner, lift, chuck and sand blast nozzle are eachcontrolled by solenoid controlled valves as is the coding mechanismdrive of the marker. This marker positioner control is subject tocommand signals from the controller 131 through its control and valveassembly 156.

Loaders 34 and 35 have control modules 157 and 158 supported oncarriages 36 and 37 and coupled with motor control systems 150 and 151to controller 131 by suitable flexible traveling cables 159 and 161.Positive pressure air conduits for pneumatic driving and blow offfunctions and vacuum conduits can be joined as flexible travelingconduits with traveling cables 159 and 161 to feed the actuatingcylinders and vacuum cups of loaders 34 and 35 at all positions of theirtraverse. Control modules 157 and 158 each include solenoid actuatedvalves for vacuum and blow off air to the vacuum cups 57, 76, 90 and 91,for the pneumatic drive valves for vacuum head drive cylinders 55, 75,87 and 95 and for lift cylinders 79 and 110.

Each grinder 21 has a control 162 for operating the grinder and thesolenoid for chuck orientation in response to signals from controller131. Control 162 also provides feedback signals of the grinder and chuckstate to controller 131.

The several ware sensors are also cabled to the controller 131 toactuate appropriate responses through the controller control. Thus, inFIG. 10, ware sensor 132 at the cradle loader signals the presence of apanel at the ware marker-positioner and controller 131 responds byactuating a marker lift.

It is to be appreciated that the apparatus disclosed and its method ofoperation lend themselves to many variations and applications. While theproducts operated upon are faceplates of panels of CRTs, it is to beappreciated that other products which are to be distributed to a numberof like processing stations could be manipulated to such stationsemploying features of his system. Further, the grinder machine workstations can be of different from those shown and other forms of workstations could be loaded and unloaded with apparatus according to thisinventions. While the timed functions of the loaders are shifted inphase in the described operation, they can be operated in phase providedtheir pick up functions occur when work pieces on the conveyors arestationary. The system can be applied to worklines having greater orfewer work stations than the sixteen illustrated. It can be employedwith work stations only on one side of the conveyor. The structure ofthe elements of the loaders, carriages and conveyors illustrated can bereplaced by other structures which perform the functions of this system.In view of the available variations, it is to be understood that thisinvention description is to be read as illustrative and not in alimiting sense.

I claim:
 1. Apparatus for distributing workpieces to a plurality of atleast three aligned workstations for the workpieces comprising aconveyor for workpieces for conveying workpieces along a path adjacentsaid plurality of workstations; a loader for transferring workpiecesbetween said conveyor and said workstations; and means to move saidloader along said conveyor to positions for transferring workpiecesbetween said conveyor and each individual workstation of said pluralityof workstations; wherein said loader has a station for engagement of aworkpiece on said conveyor, a station for release of a workpiece in saidworkstation, and a station for a workpiece intermediate said workpieceengagement station and said workpiece release station.
 2. Apparatusaccording to claim 1 wherein said loader is adapted to transfer aworkpiece from said station for engagement on said conveyor of saidintermediate station prior to transfer to said workstation.
 3. Apparatusaccording to claim 1 wherein said loader is adapted to transfer aworkpiece from said workstation to said intermediate station and isadapted to transfer a workpiece from said intermediate station to saidconveyor.
 4. Apparatus according to claim 1 wherein said means to movesaid loader along said conveyor moves said loader while a workpiece ismaintained in said intermediate station.
 5. Apparatus according to claim1 wherein said loader intermediate station includes means to orient aworkpiece for precise positioning by said loader in said workstation. 6.Apparatus for distributing workpieces to a plurality of at least threealigned workstations for the workpieces comprising a conveyor forworkpieces for conveying workpieces along a path adjacent said pluralityof workstations; a loader for transferring workpieces between saidconveyor and said plurality of workstations; means to move said loaderalong said conveyor to transfer positions proximate each of saidworkstations for transferring workpieces between said conveyor and eachindividual workstation of said plurality of workstations; and acontroller for coordinating operation of said conveyor, said means tomove said loader and said loader to transfer workpieces between saidconveyor and each individual workstation of said plurality ofworkstations in a repetitive sequence for each workpiece transfer,wherein said controller is programmed to move said conveyor to positiona workpiece at a first conveyor station adjacent a first transferposition for said loader, to position said loader at the first transferposition for pickup of a workpiece from said conveyor at said firstconveyor station, to operate said loader to pickup a workpiece from saidconveyor at said first conveyor station, to position said loader andsaid picked up workpiece at a second transfer position, and to load saidworkpiece in a workstation proximate said second transfer position. 7.Apparatus according to claim 6 wherein said controller for coordinatingoperation of said conveyor, said means to move said loader and saidloader is programmed to position said loader at a first transferposition proximate a first workstation for unloading a workpiecetherefrom, to operate said loader to unload a workpiece from said firstworkstation while at said first transfer position, to position saidloader at a second transfer position proximate a second workstation, andto operate said loader while at said second transfer position to placesaid workpiece from said first workstation on said conveyor proximatesaid second workstation.
 8. Apparatus according to claim 6 wherein saidcontroller is programmed to operate said loader at said first transferposition to remove a workpiece from a first workstation proximate saidfirst transfer position and to operate said loader while at said secondtransfer position to unload a workpiece from a second workstationproximate said second transfer position.
 9. Apparatus according to claim8 wherein said controller is programmed to operate said loader at saidsecond transfer position to deposit a workpiece removed from said firstworkstation on said conveyor.
 10. Apparatus according to claim 8 whereinsaid controller is programmed to move said conveyor to position aworkpiece to a position to be picked up by said loader while at saidsecond transfer position, and to operate said loader while at saidsecond transfer position to pickup a workpiece from said conveyor. 11.Apparatus according to claim 9 wherein said controller is programmed tomove said conveyor to position a workpiece at a position to be picked upby said loader while at said second transfer position and to operatesaid loader while at said second transfer position to pickup a workpiecefrom said conveyor.
 12. Apparatus for distributing workpieces to aplurality of aligned workstations for the workpieces comprising aconveyor for workpieces for conveying workpieces along a path adjacentsaid plurality of workstations; a loader for transferring workpiecesbetween said conveyor and said workstations; means to move said loaderalong said conveyor to transfer positions proximate each of saidworkstations for transferring workpieces between said conveyor andindividual proximate workstations; a workpiece loading station for saidconveyor; and a workpiece orienting station intermediate said loadingstation and a portion of said conveyor proximate a first of saidworkstations for orienting workpieces on said conveyor for engagement bysaid loader.
 13. Apparatus according to claim 12 wherein said workpieceorienting station includes means to mark the workpiece with theworkstation code of the workstation in which it will be loaded. 14.Apparatus according to claim 12 wherein said conveyor has deliverystations for workpieces which are proximate said workstations and areeach equally spaced at a workpiece separation on said conveyor, whereinsaid orienting station orients a workpiece on said conveyor a workpieceseparation from the first of said workpiece delivery stations andwherein said conveyor is an indexing conveyor which advances workpiecesin increments of workpiece separation.
 15. Apparatus for distributingworkpieces to a plurality of equally spaced aligned workstations for theworkpieces comprising a conveyor for conveying workpieces along a pathadjacent said plurality of workstations having a feed section and a mainsection separate from said feed section; a loader for transferringworkpieces between said conveyor and said workstations; means to movesaid loader along said conveyor to positions for transferring workpiecesbetween said conveyor and individual workstations; an indexing drivemeans for said feed section of said conveyor for advancing workpieces onsaid feed section in feed increments of a length equal to the spacing ofadjacent workstations of said plurality of workstations; and indexingdrive means for said feed section and said main section of said conveyorindexed alternately with said feed section for advancing workpieces in amultiple of said feed increments.
 16. Apparatus according to claim 15wherein said multiple of a workpiece separation is two.
 17. Apparatusaccording to claim 14 wherein said loader has transfer positions alongsaid conveyor aligned with said conveyor delivery stations in adirection normal to the conveying direction of said conveyor, andwherein said means to move said loader is an indexing drive whichindexes said loader to loader transfer positions in increments ofworkpiece separation between adjacent loader transfer positions. 18.Apparatus according to claim 17 including a support for a workpiece onsaid loader; means to cause said loader moving means to position saidloader at one of its transfer positions; means to cause said loaderwhile at said one transfer position to transfer a workpiece from saidconveyor to said support; means to cause said loader moving means toposition said loader and workpiece on said support at a second of itstransfer positions; and means to cause said loader while at said secondtransfer position to transfer the workpiece from said support to saidworkstation proximate said second transfer position.
 19. Apparatusaccording to claim 18 wherein said workpiece orienting station includesmeans to mark a workpiece with the workstation code for said workstationproximate said second transfer position; and means to advance saidconveyor with the marked workpiece to the conveyor delivery stationadjacent said one loader transfer position.
 20. Apparatus according toclaim 19 wherein said conveyor comprises a feed section and a mainsection separate from said feed section; drive means for said feedsection for advancing workpieces on said feed section one workpieceseparation; drive means for said main and feed sections for advancingworkpieces on said conveyor two workpiece separations; means to activatealternately said conveyor drive means for said feed section and saidconveyor drive means for said feed and main sections; and means toadvance a workpiece from said orienting station by said drive means forsaid main and feed sections when said one loader transfer position is aneven number of workpiece separations from said orienting station and toadvance a workpiece from said orienting station by said drive means forsaid feed section when said one loader transfer position is an oddnumber of workpiece separations from said orienting station. 21.Apparatus according to claim 1 including a workpiece receiving chuckwhich is moveable in planes normal to the direction from whichworkpieces are received in each workstation; means to align said chuckin planes normal to the direction from which workpieces are received toreceive a workpiece from said loader; and means on said loader to orienta workpiece in planes normal to the direction of delivery of workpiecesto said chuck for delivery to said aligned chuck.
 22. Apparatusaccording to claim 21 wherein said means on said loader to orient aworkpiece includes a lift to support said workpiece, camming means onsaid loader to guide said workpiece into an aligned orientation forloading on said chuck; and control means for said lift to lower saidworkpiece into engagement with said camming means.
 23. Apparatusaccording to claim 22 wherein said means on said loader to orient aworkpiece is between said conveyor and said workstation.
 24. Apparatusfor distributing workpieces to a plurality of aligned workstations forthe workpieces comprising a conveyor for workpieces for conveyingworkpieces along a path adjacent said plurality of workstations; aworkpiece orienting station for said conveyor for positioning workpieceson said conveyor with a first orientation; a loader for transferringworkpieces with the first orientation between said conveyor and saidworkstations; means to move said loader along said conveyor to positionsfor transferring workpieces between said conveyor and individualworkstations; wherein said loader has a station for engagement of aworkpiece which has been processed in a workstation and a station forrelease onto said conveyor of a workpiece which has been processed in aworkstation; and means on said loader to reorient a workpiece receivedfrom said workstation for delivery to said conveyor in a secondorientation whereby processed workpieces on said conveyor aredistinguished from workpieces which have not been processed in aworkstation.
 25. Apparatus according to claim 24 wherein said means onsaid loader to reorient a workpiece includes a lift, a rotatableworkpiece support on said lift, and control means to lower said liftwith a workpiece, rotate said support and raise said lift.
 26. Apparatusaccording to claim 25 wherein said means on said loader to reorient aworkpiece is between said conveyor and said workstation.
 27. Apparatusfor distributing workpieces to a plurality of aligned workstations forthe workpieces comprising a conveyor for workpieces for conveyingworkpieces along a generally horizontal path adjacent said plurality ofworkstations; a loader for transferring workpieces between said conveyorand said workstations; means to index said loader along said conveyor topositions for transferring workpieces between said conveyor andindividual workstations; means to index said conveyor to locateworkpieces at transfer stations associated with individual workstationsto enable transfer of workpieces from said conveyor to said workstationsby said loader; a vertical shaft on said loader; means to oscillate saidshaft through a ninety degree arc around the vertical; four arms inquadrature extending generally horizontally from said shaft and arrangedto oscillate with said shaft; a workpiece holding mechanism on each ofsaid four arms; one pair of opposed arms extending perpendicular to thedirection of advance of said conveyor when said shaft is at a firstextreme of rotation; a second pair of opposed arms extending parallelwith the direction of advance of said conveyor when said shaft is at afirst extreme of rotation; workpiece supports on said loader beneatheach of said second pair of opposed arms when said shaft is at the firstextreme of rotation; a first arm of said one pair extending toward saidconveyor and another arm of said one pair extending toward saidworkstation when said shaft is at the first extreme of rotation; meansto actuate said holding means on said first arm to engage and pickup aworkpiece on said conveyor; means to rotate said shaft with said one armto a second extreme of rotation to a position above one of saidworkpiece supports on said loader; means ro release said holding meansfor a workpiece on said one arm while it is above said one of saidworkpiece supports; means to rotate said shaft with said one arm to saidfirst extreme of rotation from said second extreme of rotation. 28.Apparatus according to claim 27 including means to actuate said holdingmeans on a second arm which is one of said second pair located abovesaid one support when said shaft is at the first extreme of rotation toengage and pick up a workpiece on said one support one said loader whensaid shaft is at the first extreme of rotation; means to rotate saidshaft with said second arm to said second extreme of rotation to aposition above said workstation; means to release said holding means fora workpiece on said second arm while it is above said workstation. 29.Apparatus according to claim 28 including means to actuate said holdingmeans on a third arm which is the other of said first pair located abovesaid workstation when said shaft is at the first extreme of rotation toengage and pickup a workpiece on said workstation when said shaft is atthe first extreme of rotation; means to rotate said shaft with saidthird arm to said second extreme of rotation to a position above saidother support on said loader; means to release said holding means for aworkpiece on said third arm while it is above said other support. 30.Apparatus according to claim 29 including means to actuate said holdingmeans on a fourth arm which is the other said second pair located abovesaid second support on said loader when said shaft is at the secondextreme of rotation to engage and pickup a workpiece on said secondsupport when said shaft is at the first extreme of rotation; means torotate said shaft with said fourth arm to said second extreme ofrotation to a position above said conveyor; means to release saidholding means for a workpiece on said fourth arm while it is above saidconveyor.
 31. Apparatus according to any of claims 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 21 through 30 wherein saidworkpiece is a cathode ray tube faceplate panel; said workstations aregrinders for said faceplates; said loading means include a vacuum cupengageable with said faceplates; and means to selectively impose avacuum within said vacuum cup while said cup is engaged with afaceplate.
 32. An automatic system for processing workpiecescomprising:a workpiece conveyor; a plurality of workpiece processingmachines aligned along one side of said conveyor; transfer mechanismadapted to transfer workpieces between said conveyor and said machines;moving means to move said transfer mechanism along said conveyor; meansto control the motion of said conveyor to position workpieces adjacentsaid machines; means to control the motion of said moving means toposition said transfer mechanism adjacent said machines; means tocontrol said transfer mechanism to transfer a workpiece from saidconveyor to an adjacent processing machine and simultaneously totransfer a processed workpiece from said processing machine to saidconveyor; and control means to coordinate the operation of said conveyormotion control means, said moving means control means and said transfermechanism control means with respect to said machines to transferworkpieces between said conveyor and said machines.
 33. An automatedsystem according to claim 32 including:a second plurality of workpieceprocessing machines aligned along a second side of said conveyor;transfer mechanism adapted to transfer workpieces between said conveyorand said machines of said second plurality; means to control the motionof said conveyor to position workpieces adjacent said machines of saidsecond plurality; means to position said transfer mechanism adjacentsaid machines of said second plurality; means to control said transfermechanism to transfer a workpiece from said conveyor to an adjacentmachine of said second plurality and simultaneously to transfer aprocessed workpiece from said machine to said conveyor; and controlmeans to coordinate the operation of said conveyor motion control means,said transfer mechanism positioning means and said transfer mechanismcontrol means with respect to said machines of said second plurality totransfer workpieces between said conveyor and said machines of saidsecond plurality.
 34. An automated system according to claim 33 whereinsaid transfer mechanism adapted to transfer workpieces between saidconveyor and said machines of said second plurality is a second transfermechanism; and including control means for said second transfermechanism; second moving means to move said second transfer mechanismalong said conveyor; and means to control said second transfermechanism.
 35. An automated system according to claim 34 wherein saidcontrol means to coordinate coordinates the operation of said controlmeans for said second moving means and said means to control said secondtransfer mechanism with the conveyor motion control means, said firstmentioned moving means control means and said first mentioned transfermechanism control means with respect to said first mentioned pluralityand said second plurality of machines simultaneously to transferworkpieces between said conveyor and a machine of each of said firstmentioned and said second plurality of said machines.
 36. An automatedsystem according to claim 32 wherein said workpiece processing machineseach have a predetermined interval for processing a workpiece andwherein said control means to coordinate the operation of said conveyormotion control means, said moving means control and said transfermechanism control coordinates control for a workpiece transfer for eachof said plurality of processing machines in a time interval equal to orless than said predetermined time interval.
 37. An automated systemaccording to claim 33 wherein said workpiece processing machines eachhave a predetermined time interval for processing a workpiece andwherein said control means to coordinate operation coordinates controlfor a workpiece transfer for each of said first mentioned plurality andsaid second plurality of processing machines in a time interval nogreater than said predetermined time interval.
 38. An automated systemaccording to claim 32 wherein said workpiece conveyor comprises a firstsection and a second section and including a workpiece loading stationfor loading said first section;a workpiece orientor for positioningworkpieces on said first section; a delivery station on said firstsection for advancement of oriented workpieces to said second section;means to advance a workpiece on said first section from said loadingstation to said orientor and from said orientor to said deliverystation; and means to advance a workpiece to said first section inconjunction with the advance of a workpiece on said second section. 39.A conveyor having an elongate path for distribution of workpieces to aplurality of delivery stations along said conveyor path, said conveyorcomprising a feed conveyor section; a main conveyor section; a feeddrive to drive said feed section independent of said main section; amain drive to drive said feed and main sections together; feed drivecontrol for said feed drive; main drive control for said main drive; aconveyor control for alternately and imtermittently activating said maindrive control and said feed drive control; and a conveyor loaderactivated by said conveyor control to place a workpiece on a receivingposition on said feed section preceding the actuation of each drivecontrol.
 40. A combination according to claim 39 wherein said deliverystations are spaced along said path at equal delivery station incrementspacings, wherein said feed drive control advances said feed section onedelivery station increment and wherein said main drive control advancessaid feed and main sections two delivery station increments.
 41. Acombination according to claim 39 wherein said conveyor controlactivates said conveyor loader.
 42. A combination according to claim 39including a workpiece orientor for positioning the workpieces on saidfeed section of the conveyor arranged to pick up a workpiece on saidfeed section, orient the workpiece while free of said feed section andreplace the oriented workpiece on said feed section one work stationincrement preceding the first delivery station along said conveyor path.43. A combination according to claim 39 including a workpiece marker forapplying indicia to a workpiece according to the delivery station towhich the workpiece is directed.
 44. A combination according to claim 39including means to assign each workpiece delivered to said feed sectionto an individual predetermined delivery station and means to mark saidworkpiece with an indicator for said assigned station.
 45. A combinationaccording to claim 44 wherein each delivery station delivers workpiecesfor a work station on a first and a second side of said conveyor andwherein there are a finite number (n) of delivery stations along saidconveyor path; means to maintain said conveyor stationary following eachtwo increment advance of said main drive whereby workpieces on saidconveyor are positioned for delivery at their assigned delivery stationson the first and second sides spaced n/2 intervals along said conveyor.46. A combination according to claim 39 includes means to inhibitdelivery of a workpiece to individual delivery stations; and means toinhibit said conveyor loader for the workpiece receiving position onsaid conveyor which is to be conveyed to said inhibited deliverystation.
 47. A combination according to claim 46 including means toassign each workpiece delivered to said feed section to an individualpredetermined delivery station; means to mark said workpiece with anindicator for said assigned station; and means to inhibit said means toassign and said means to mark for the workpiece to be loaded at theworkpiece receiving position on said conveyor which is to be conveyed tosaid inhibited delivery station.
 48. A workpiece transfer mechanismcomprising a pillar; a plurality of arms mounted radially on said pillarat equal spacings around said pillar; a workpiece pickup head mounted oneach arm; a linkage mounting each pickup head for extension from andretraction toward its respective mounting arm; each of said arms havinga home position at which a workpiece is picked up and being swingablethrough an arc around said pillar to a delivery position at which aworkpiece is deposited; means to control said workpiece pick-up head;means to control said linkage extension and retraction; and means tooscillate said arms in unison through the arc around said pillar tosuccessively transfer workpieces from the home to the delivery positionof each arm around said pillar.
 49. A combination according to claim 48wherein said plurality of arms is four said arms are mounted inquadrature to each other and said arc is 90°.
 50. A combinationaccording to claim 48 wherein said home station for a first of said armsis a workpiece supply position; and a first dwell support for aworkpiece at said delivery position for said first arm.
 51. Acombination according to claim 50 wherein said first dwell supportincludes a workpiece orientor at said delivery position for said firstarm.
 52. A combination according to claim 50 wherein said home stationfor a second of said arms is at said first dwell support for aworkpiece; and said delivery position for said second arm is at aworkpiece processor.
 53. A combination according to claim 52 whereinsaid home station for a third of said arms is at the workpieceprocessor; and a second dwell support for a workpiece at said deliveryposition for said third arm.
 54. A combination according to claim 53wherein said workpiece dwell support includes means to reorient saidworkpiece.
 55. A combination according to claim 53 wherein said homestation for a fourth of said arms is at said second workpiece dwellsupport; and said delivery position for said fourth arm is at the supplyposition.
 56. A combination according to claim 48 including a carriagefor said transfer mechanism; a rail extending along a predetermined pathfor said carriage; and means to drive said carriage along said rail topredetermined transfer stations along said path.
 57. A combinationaccording to claim 56 including a first dwell support for a workpiecesupported by said carriage; and wherein said home station for a first ofsaid arms is a workpiece supply position; and said first dwell supportis at said delivery position for said first arm.
 58. A combinationaccording to claim 57 including a second dwell support for a workpiecesupported by said carriage; and wherein said home station for a secondof said arms is said first dwell support; said delivery station for saidsecond arm is at a workpiece processor; said home station for a third ofsaid arms is the workpiece processor; and said delivery station for saidthird arm is said second dwell support.
 59. A combination according toclaim 58 including a workpiece orientor at said first dwell support fororienting a workpiece for placement in a workpiece processor; and meansto control said orientor.
 60. A combination according to claim 56including a transfer control to coordinate control of said means tocontrol said workpiece pickup heads, said means to control said linkageextenstion and retraction, said means to oscillate said arms, and saidmeans to drive said carriage.
 61. A combination according to claim 60wherein said transfer control includes means to coordinate control ofsaid means to control said orientor with said pickup head; said linkage,said means to oscillate and said means to drive said carriage. 62.Apparatus according to claim 2 wherein said loader includes a secondstation for the workpiece intermediate said station for engagement of aworkpiece on said conveyor and said station for release of a workpiecein said workstation, and said loader is adapted to transfer a workpiecefrom said workstation to said second station and is adapted to transfera workpiece from said second station to said conveyor.
 63. Apparatusaccording to claim 62 wherein said loader is adapted to simultaneouslytransfer a workpiece from said station for engagement of a workpiece onsaid conveyor to said first mentioned intermediate station, transfer aworkpiece from said first mentioned intermediate station to said stationfor release of a workpiece in said workstation, transfer a workpiecefrom said workstation to said second intermediate station, and transfera workpiece from said second intermediate station to said conveyor. 64.Apparatus according to claim 62 wherein said loader is adapted to conveya workpiece in each of said first mentioned and said second intermediatestations as said means to move said loader moves said loader betweensuccessive workstations.